OK after alot of time and testing found the issues

it was not as simple at it may have appeared , and a combination of the hardware and the firmware changes fixed my issues
some of the problems solved were mainly to do with how the edge interupts were enabled and triggered

i found by adding some delay between setting the trigger points and enabling the keys that trigger helped
also that i forgot that when i turn off external power to modules 1 did not retain the settings and need to be redone in the ISR

these gave the impression that the ISR was not returning to the main program , where it was mainly how it was triggered and retriggered


cheers

Sheldon